The Experts below are selected from a list of 201 Experts worldwide ranked by ideXlab platform
Gordon W Lorimer - One of the best experts on this subject based on the ideXlab platform.
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precipitation reactions in magnesium Rare Earth Alloys containing yttrium gadolinium or dysprosium
Scripta Materialia, 2003Co-Authors: P J Apps, H Karimzadeh, J F King, Gordon W LorimerAbstract:Abstract Precipitation reactions have been evaluated in three magnesium-Rare Earth Alloys, containing yttrium, gadolinium or dysprosium. Differences have been noted in precipitate morphology, volume fraction and formation kinetics. These features have been combined with phase composition data and related to mechanical properties.
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Phase compositions in magnesium-Rare Earth Alloys containing yttrium, gadolinium or dysprosium
Scripta Materialia, 2003Co-Authors: P J Apps, H Karimzadeh, J F King, Gordon W LorimerAbstract:Abstract Phase compositions have been investigated, using thin foil energy dispersive X-ray spectroscopy, in three magnesium-Rare Earth Alloys, containing yttrium, gadolinium or dysprosium. Compositions are suggested for the as-cast eutectic and β precipitate phases and possible compositions for the β 1 precipitate phases are discussed.
P J Apps - One of the best experts on this subject based on the ideXlab platform.
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precipitation reactions in magnesium Rare Earth Alloys containing yttrium gadolinium or dysprosium
Scripta Materialia, 2003Co-Authors: P J Apps, H Karimzadeh, J F King, Gordon W LorimerAbstract:Abstract Precipitation reactions have been evaluated in three magnesium-Rare Earth Alloys, containing yttrium, gadolinium or dysprosium. Differences have been noted in precipitate morphology, volume fraction and formation kinetics. These features have been combined with phase composition data and related to mechanical properties.
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Phase compositions in magnesium-Rare Earth Alloys containing yttrium, gadolinium or dysprosium
Scripta Materialia, 2003Co-Authors: P J Apps, H Karimzadeh, J F King, Gordon W LorimerAbstract:Abstract Phase compositions have been investigated, using thin foil energy dispersive X-ray spectroscopy, in three magnesium-Rare Earth Alloys, containing yttrium, gadolinium or dysprosium. Compositions are suggested for the as-cast eutectic and β precipitate phases and possible compositions for the β 1 precipitate phases are discussed.
James E. Wittig - One of the best experts on this subject based on the ideXlab platform.
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Precipitate crystallography and morphology in undercooled, rapidly solidified titanium Rare Earth Alloys
Scripta Materialia, 1997Co-Authors: Milo V. Kral, William H. Hofmeister, James E. WittigAbstract:In the present experiments on three titanium-Rare Earth Alloys (Ti-1.4 at. % Ce, Ti-1.7 Er and Ti-1.5 La), electromagnetic levitation techniques allowed large bulk liquid undercoolings to be induced prior to rapid solidification via splat quenching. The resulting microstructures are quite different from those found in earlier rapid solidification experiments. As-solidified Ti-Ce and Ti-Er Alloys exhibited a distribution of elemental Rare Earth precipitates within regularly-spaced planar or curved sheets throughout an equiaxed {alpha} Ti matrix. The Ti-La alloy contained randomly distributed metallic lanthanum precipitates within equiaxed {alpha} Ti grains. As in previous studies, annealing treatments resulted in oxidation of the particles. However, annealed precipitates showed different crystal structures than those identified in prior research. This paper describes the unique precipitate morphologies, structures and orientation relationships present in undercooled and rapidly solidified titanium-Rare Earth Alloys.
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Undercooled rapidly solidified titanium-Rare Earth Alloys
1995Co-Authors: Milo V. Kral, William H. Hofmeister, James E. WittigAbstract:The microstructural effects of undercooling on eight titanium-Rare Earth Alloys were investigated. Electromagnetic levitation allowed cooling of the liquid well below the liquidus prior to nucleation/solidification. For each alloy, a series of samples was splat quenched with systematically varied undercoolings. The resulting materials were characterized by scanning and transmission electron microscopy in the as-quenched and annealed states. Typically, rapid solidification of titanium-Rare Earth Alloys results in supersaturation of {alpha} Ti and precipitation occurs during annealing treatments. In these experiments, evidence of precipitation during cooling through the {beta}/{alpha} transus was observed and has been attributed to an interphase boundary precipitation mechanism. The results of undercooling/splat quench experiments were utilized to select materials for undercool/rapid quench technology (URQT) processing. This novel technique combines electromagnetic levitation, an ultrahigh (10{sup {minus}8} torr) vacuum system and a three meter drop tube with melt spinning via a variable speed copper wheel. Materials processed by this method exhibited homogeneous solidification microstructures uncharacteristic of conventional melt spinning, and small (1 nm) interphase boundary precipitates in the as-quenched state.
David Griffiths - One of the best experts on this subject based on the ideXlab platform.
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explaining texture weakening and improved formability in magnesium Rare Earth Alloys
Materials Science and Technology, 2015Co-Authors: David GriffithsAbstract:AbstractWrought magnesium Alloys are Rarely used due to their poor formability which is caused by strong textures created during processing. Addition of Rare Earth (RE) elements including Y, Ce, La, Gd and Nd weakens these strong basal textures and significantly improves formability. Developing a mechanistic understanding of this effect is critical in leading alloy design towards a new class of highly formable magnesium Alloys. This fall in texture intensity occurs during recrystallisation and only requires very low solute RE additions, 0·01 at.-% in the magnesium–Ce case. These additions retard dynamic recrystallisation and increase non-basal slip; however, a full understanding of the RE effect has yet to be obtained, with a variety of mechanisms proposed. Recent research in these areas is critically reviewed.
C Boeglin - One of the best experts on this subject based on the ideXlab platform.
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role of critical spin fluctuations in ultrafast demagnetization of transition metal Rare Earth Alloys
Physical Review B, 2013Co-Authors: Victor Lopezflores, N Bergeard, V Halte, C Stamm, N Pontius, M Hehn, Edwige Otero, Emmanuel Beaurepaire, C BoeglinAbstract:Ultrafast magnetization dynamics induced by femtosecond laser pulses have been measured in ferrimagnetic Co0.8Gd0.2, Co0.74Tb0.26, and Co0.86Tb0.14 Alloys. Using element sensitivity of x- ray magnetic circular dichroism at the Co L-3, Tb M-5, and Gd M-5 edges, we see that the demagnetization dynamics is element dependent. We show that a thermalization time as fast as 280 +/- 30 fs is observed for the Rare Earth in the alloy when the excited-state temperature is below the compensation temperature. It is limited to 500 +/- 100 fs when the excited-state temperature is below the Curie temperature (T-C). Therefore, for transition-metal Rare-Earth Alloys, we propose that critical spin fluctuations in the vicinity of T-C reduce the demagnetization rates of the 4f electrons, whereas far from T-C the limited demagnetization rates should be avoided.
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Role of critical spin fluctuations in ultrafast demagnetization of transition-metal Rare-Earth Alloys
Physical Review B, 2013Co-Authors: Víctor López-flores, N Bergeard, V Halte, C Stamm, N Pontius, M Hehn, Edwige Otero, Emmanuel Beaurepaire, C BoeglinAbstract:Ultrafast magnetization dynamics induced by femtosecond laser pulses have been measured in ferrimagnetic Co${}_{0.8}$Gd${}_{0.2}$, Co${}_{0.74}$Tb${}_{0.26}$, and Co${}_{0.86}$Tb${}_{0.14}$ Alloys. Using element sensitivity of x-ray magnetic circular dichroism at the Co ${L}_{3}$, Tb ${M}_{5}$, and Gd ${M}_{5}$ edges, we see that the demagnetization dynamics is element dependent. We show that a thermalization time as fast as 280 $\ifmmode\pm\else\textpm\fi{}$ 30 fs is observed for the Rare Earth in the alloy when the excited-state temperature is below the compensation temperature. It is limited to 500 $\ifmmode\pm\else\textpm\fi{}$ 100 fs when the excited-state temperature is below the Curie temperature (${T}_{C}$). Therefore, for transition-metal Rare-Earth Alloys, we propose that critical spin fluctuations in the vicinity of ${T}_{C}$ reduce the demagnetization rates of the 4$f$ electrons, whereas far from ${T}_{C}$ the limited demagnetization rates should be avoided.
